Cystic-like maxillary sinus hypoplasia

Description

A woman in her 50s with Sjögren’s syndrome characterised by xerostomia, xerophthalmia, skin xerosis and asthenia was referred to the Unit of Oral Surgery and Implantology for management of a maxillary lesion discovered on a panoramic X-ray (OPT) carried out as part of her oral check-up. The extra-oral and intra-oral examinations were unremarkable. Dental examination revealed poor oral hygiene, generalised chronic periodontitis, absence of teeth 27 and 36, and multiple caries affecting teeth 14, 15, 16 and 17. The OPT X-ray examination showed a well-defined unilocular radiolucent lesion in the left zygomatic bone. The lesion measured 8 mm in width and 10 mm in height and was reminiscent of a cystic lesion (figure 1). In order to investigate this lesion, a 3D cone beam CT (CBCT) examination was performed (figure 2B–D). It revealed the absence of osteolytic lesion in the left zygomatic bone. The ‘left zygomatic cyst’ visualised on the OPT X-ray was a result of a projection of part of the left maxillary sinus antrum which was partially aerated and contrasted strongly with an enlarged bony frame. The CBCT showed chronic inflammation of both maxillary sinuses, with scanographic signs of acutisation in the form of foamy filling within them, combining coarse calcifications in frame and sclerosis with an aspect of atelectasis of their bone walls, bilaterally hypoplastic in appearance. Otherwise, the rest of the sinus and nasal cavities were free and there was no marked lowering of the orbital floors or obvious enophthalmos visible in this examination. These results combined with the patient’s history of Sjögren’s syndrome indicate a chronic hypoplastic sinusopathy secondary to her autoimmune inflammatory disease. The volumes of the left maxillary sinus were calculated using an OSIRIX medical image software which provided a value of 2.4687 cm³, lower than the values found in patients aged over 20 years ranging from 4.56 to 35.21 cm³ (mean 14.71±SD 6.33 cm³).¹

Figure 1.

OPT.

Figure 2.

(A–D). CBCT cross-section frontal, transversal and sagittal. CBCT, cone beam CT.

Hypoplasia of the maxillary sinuses is a rare condition.^{2 3} The incidence varies between 1.5% and 10%.² Maxillary sinus hypoplasia (MSH) is classified into three types depending on embryological development of the sinus and uncinate process. Type I MSH is characterised by mild hypoplasia of the maxillary sinus, normal uncinate process and a well-developed infundibular passage. Type II MSH has a significant hypoplasia of the maxillary sinus, hypoplastic or absent uncinate process and absent or pathologic infundibular passage. Type III MSH is characterised by near absence of the uncinate process and cleft-like maxillary sinus.⁴ Our case corresponds to type II.

MSH can be congenital or acquired.^{3 5 6} Congenital causes are developmental arrest due to infection, radiation, injury, congenital first arch syndrome and developmental anomalies such as osteodysplasia, craniosynostosis and Down syndrome.^{3 5} Acquired etiological causes are post-traumatic deformity due to fracture or surgery in the sinus region, inflammatory osteitis, thalassemia, cretinism and tumours causing osteitis.^{3 7} Although the majority of those affected are unaware of their condition and asymptomatic,^{3 5} others may have symptoms such as facial pain, runny nose, headache and voice alteration.⁵ In conventional radiological examination of the OPT type, opacification of the maxillary sinus can be misdiagnosed as inflammatory mucosal thickening without evoking hypoplasia of the sinus, a tumour or other pathologies.² The CBCT examination in the evaluation of rhinosinus affections is required to make the diagnosis.⁸ In this case, the patient was asymptomatic and the diagnosis of MSH was based on the CBCT examination during which we explored an atypical cystic-like feature on the OPT X-ray image.

Patient’s perspective.

During a routine dental check-up, I was found to have an unusual cystic lesion on a radiograph. The hospital’s doctors made an additional X-ray examination that revealed not a cyst but a maxillary sinus lesion related to my Sjögren’s syndrome. I was relieved and happy to know that a surgical intervention was not necessary.

Learning points.

• Maxillary sinus hypoplasia is rare; definitive diagnosis is made based on a cone beam CT examination.

• It may be associated, as in this case, with Sjögren’s syndrome.

• On an OPT X-ray, opacification of the maxillary sinus can be observed and misdiagnosed as an inflammatory mucosal thickening without necessarily evoking other pathological conditions such as a hypoplasia of the sinus or even a tumour.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).